Campbell Diane R, Powers John M
Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA Rocky Mountain Biological Laboratory, Crested Butte, CO 81224, USA
Rocky Mountain Biological Laboratory, Crested Butte, CO 81224, USA Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA.
Proc Biol Sci. 2015 Jun 7;282(1808):20150178. doi: 10.1098/rspb.2015.0178.
Climate has the potential to influence evolution, but how it influences the strength or direction of natural selection is largely unknown. We quantified the strength of selection on four floral traits of the subalpine herb Ipomopsis sp. in 10 years that differed in precipitation, causing extreme temporal variation in the date of snowmelt in the Colorado Rocky Mountains. The chosen floral traits were under selection by hummingbird and hawkmoth pollinators, with hawkmoth abundance highly variable across years. Selection for flower length showed environmental sensitivity, with stronger selection in years with later snowmelt, as higher water resources can allow translation of pollination success into fitness based on seed production. Selection on corolla width also varied across years, favouring narrower corolla tubes in two unusual years with hawkmoths, and wider corollas in another late snowmelt year. Our results illustrate how changes in climate could alter natural selection even when the primary selective agent is not directly influenced.
气候有可能影响进化，但它如何影响自然选择的强度或方向在很大程度上尚不清楚。我们量化了亚高山草本植物羽扇豆属四种花部性状的选择强度，研究历时10年，期间降水不同，导致科罗拉多落基山脉融雪日期出现极端的时间变化。所选的花部性状受到蜂鸟和天蛾传粉者的选择作用，且天蛾的数量年际变化很大。对花长度的选择表现出环境敏感性，在融雪较晚的年份选择作用更强，因为更高的水资源量能使基于种子产量的授粉成功转化为适合度。对花冠宽度的选择也随年份而变化，在有天蛾出现的两个特殊年份中倾向于较窄的花冠管，而在另一个融雪较晚的年份则倾向于较宽的花冠。我们的结果说明了即使主要选择因子没有直接受到影响，气候的变化也可能改变自然选择。
